diff --git a/packages/core/pattern.mjs b/packages/core/pattern.mjs
index a85226a8..f5b0c676 100644
--- a/packages/core/pattern.mjs
+++ b/packages/core/pattern.mjs
@@ -2998,6 +2998,24 @@ export const extend = stepRegister('extend', function (factor, pat) {
   return pat.fast(factor).expand(factor);
 });
 
+/**
+ * *Experimental*
+ *
+ * `replicate` is similar to `fast` in that it increases its density, but it also increases the step count
+ * accordingly. So `stepcat("a b".replicate(2), "c d")` would be the same as `"a b a b c d"`, whereas
+ * `stepcat("a b".fast(2), "c d")` would be the same as `"[a b] [a b] c d"`.
+ *
+ * TODO: find out how this function differs from extend
+ * @example
+ * stepcat(
+ *   sound("bd bd - cp").replicate(2),
+ *   sound("bd - sd -")
+ * ).pace(8)
+ */
+export const replicate = stepRegister('replicate', function (factor, pat) {
+  return pat.repeatCycles(factor).fast(factor).expand(factor);
+});
+
 /**
  * *Experimental*
  *
diff --git a/packages/mondough/mondough.mjs b/packages/mondough/mondough.mjs
index b7ee8378..e2c6dc9a 100644
--- a/packages/mondough/mondough.mjs
+++ b/packages/mondough/mondough.mjs
@@ -5,7 +5,7 @@ import {
   slow,
   seq,
   stepcat,
-  extend,
+  replicate,
   expand,
   pace,
   chooseIn,
@@ -36,7 +36,7 @@ lib.square = (...args) => stepcat(...args).setSteps(1);
 lib.angle = (...args) => stepcat(...args).pace(1);
 lib['*'] = fast;
 lib['/'] = slow;
-lib['!'] = extend;
+lib['!'] = replicate;
 lib['@'] = expand;
 lib['%'] = pace;
 lib['?'] = degradeBy; // todo: default 0.5 not working..
diff --git a/test/__snapshots__/examples.test.mjs.snap b/test/__snapshots__/examples.test.mjs.snap
index 937d4279..d7e13d4d 100644
--- a/test/__snapshots__/examples.test.mjs.snap
+++ b/test/__snapshots__/examples.test.mjs.snap
@@ -8307,6 +8307,33 @@ exports[`runs examples > example "repeatCycles" example index 0 1`] = `
 ]
 `;
 
+exports[`runs examples > example "replicate" example index 0 1`] = `
+[
+  "[ 0/1 → 1/8 | s:bd ]",
+  "[ 1/8 → 1/4 | s:bd ]",
+  "[ 3/8 → 1/2 | s:cp ]",
+  "[ 1/2 → 5/8 | s:bd ]",
+  "[ 5/8 → 3/4 | s:bd ]",
+  "[ 7/8 → 1/1 | s:cp ]",
+  "[ 1/1 → 9/8 | s:bd ]",
+  "[ 5/4 → 11/8 | s:sd ]",
+  "[ 3/2 → 13/8 | s:bd ]",
+  "[ 13/8 → 7/4 | s:bd ]",
+  "[ 15/8 → 2/1 | s:cp ]",
+  "[ 2/1 → 17/8 | s:bd ]",
+  "[ 17/8 → 9/4 | s:bd ]",
+  "[ 19/8 → 5/2 | s:cp ]",
+  "[ 5/2 → 21/8 | s:bd ]",
+  "[ 11/4 → 23/8 | s:sd ]",
+  "[ 3/1 → 25/8 | s:bd ]",
+  "[ 25/8 → 13/4 | s:bd ]",
+  "[ 27/8 → 7/2 | s:cp ]",
+  "[ 7/2 → 29/8 | s:bd ]",
+  "[ 29/8 → 15/4 | s:bd ]",
+  "[ 31/8 → 4/1 | s:cp ]",
+]
+`;
+
 exports[`runs examples > example "reset" example index 0 1`] = `
 [
   "[ 0/1 → 1/8 | s:hh ]",